Retinoblastoma

What is retinoblastoma?

Retinoblastoma is a rare intraocular cancerous tumour, usually occurring before the age of 5. It affects one birth in 20,000. This represents 4-5 new cases diagnosed each year for the Swiss population. 

It accounts for about 4% of all paediatric cancers. However, it is the most common intraocular malignancy in children. 

Retinoblastoma is a genetic disease, but only 10% of new cases diagnosed have a relative also affected by the disease. It affects boys and girls with the same frequency. 

It can occur in only one eye, this is called unilateral retinoblastoma (70% of cases). Or both: this is called bilateral retinoblastoma (30% of cases). Each eye can develop one or more tumours.

The disease develops from immature cells of the retina, called retinoblasts. The retina lines the inner face of the eyeball and is the light-sensitive tissue essential for vision. 

If left untreated, retinoblastoma gradually destroys vision and can develop into nearby structures (the orbit, the optic nerve and the brain). If it spreads throughout the body, it is life-threatening. Hence the importance of its early diagnosis. However, retinoblastoma has an excellent chance of recovery if it is detected in time (survival rate of more than 95%).

What are clinical signs of retinoblastoma in children?

The most common clinical manifestation of retinoblastoma is leukocoria. This term refers to an abnormally whitish reflection of the pupil instead of the black reflection (or red in the case of a photo with flash). It is also known as a cat’s eye.

The second most common sign is strabismus, which is detected when one of the eyes does not seem to be looking at the target but is turned towards the ear (divergent strabismus) or towards the nose (convergent strabismus).

However, both leukocoria and strabismus can be the manifestation of other eye diseases. A complete examination of the eye with a dilated fundus by an ophthalmologist is necessary to bear out the diagnosis or otherwise.

More rarely, other symptoms can be found in a child with retinoblastoma, such as:

• A red and painful eye
• Visual impairment
• Abnormal shape of pupil
• Inflammation of the orbit

What causes retinoblastoma in children?

The disease is caused by an abnormality (mutation) of chromosome 13 where the RB1 gene for predisposition to retinoblastoma is located, part of which is defective or missing. Chromosomes are the components of a cell that contain genetic information. RB1 is one of the genes responsible for controlling cell division. In children with a mutation of the RB1 gene, unregulated cell division leads to the occurrence of retinal tumours.

What are the types of retinoblastomas?

There are three categories of retinoblastomas:

1. Nonhereditary retinoblastoma: it is the most common form of the disease (60%). In this case, the child has not inherited a genetic mutation. The latter occurred randomly during cell replication in the RB1 gene, some time after conception (the union of the sperm and the egg).
2. Sporadic hereditary retinoblastoma: in this case, the mutation of the RB1 gene occurs in the egg or sperm before conception and is transmitted to the child (30% of cases).
3. Hereditary familial retinoblastoma: in this case (10%), the child has inherited the mutation of the RB1 gene from a family member with retinoblastoma or simply carrying the mutation without the disease having manifested itself or having required treatment.

In children with hereditary forms, retinoblastoma usually develops in both eyes. Moreover, because they carry a genetic abnormality present in all the cells of their body, these children have a lifelong predisposition for a second cancer and require appropriate medical follow-up.

How can screening be carried out in children?

Retinoblastoma has an excellent chance of recovery if it is detected early. It is therefore important that parents are attentive to the eyes of their children from their first months.

If the signs of retinoblastoma are detected by the parents and/or the paediatrician, an examination of the back of the eye is carried out to confirm the diagnosis and draw up an accurate assessment of the lesions. Early detection of retinoblastoma increases the chances of preserving the child’s eye and vision, while reducing the risk of developing a second cancer.

What is the treatment of retinoblastoma?

The treatment of a child with retinoblastoma is very specific. Each case is unique. For all patients, however, the goal is above all to save the child’s life, then to try to save the eye and finally to preserve vision. Thanks to current treatment methods, retinoblastoma is cured in 95% of cases. Several treatments are available for treating retinoblastoma. All treatments are performed under general anaesthesia, except for chemotherapy, which is administered intravenously.

At the Jules-Gonin Ophthalmic Hospital, the treatment is specifically tailored to each patient. Treatment is decided according to different factors:

• Age of the child
• Unilateral (only one eye) or bilateral disease
• The stage of the disease (risk of extension and presence of metastases in particular)
• The response to possible treatments previously administered in other centres.

Find out more about children's visual disorders

Do you want to learn more about a particular visual condition? Discover our pages on strabismus, congenital glaucoma, and hyperopia. We explain these visual disorders and tell you how to treat them to preserve your children’s visual acuity.